“We urge you and those within your Department to immediately release guidance pending within the HHS related to the implementation of the biosimilar pathway,” they added.

Biosimilars have been in wide use in Europe and according to Express Scripts, the largest pharmacy benefit management company, their wider use could save the U.S. healthcare system more than $250 billion in the next few years.

Last week the FDA said it was reviewing Sandoz’s biosimilar Zarzio, which could reduce infections in cancer patients. If approved, it would be the first biosimilar to hit the U.S. market and open the floodgates for similar products.

“We assume that FDA and Sandoz had conversations about key issues … and that the FDA is engaged in conversations with other manufacturers who intend to file biosimilar applications in the future,” the two GOP lawmakers wrote.

They noted the FDA is required to release guidance to industry under the 2010 Biologics Price Competition and Innovation Act (BPCIA) but has yet to do so.

“These meetings should not be the only or primary means by which BPCIA implementation policies are developed,” they added. “Does the FDA intend to approve the first biosimilar before policies on these key scientific questions are publicly released?”